Download What is DNA? - Mr. C at Hamilton

DNA
Edited by: Mr. Cistaro
01/13/13
•What is DNA?
 Deoxyribonucleic
 Made
Acid
up of 4 “chemical bases”
 A=Adenine
 G=Guanine
 T=Thymine
 C=Cytosine
 Made
up of 2 “backbones”
 Sugar
 Phosphate
 The
base bonds to the sugar
•What is DNA?
 When
it comes to DNA…
 A=Adenine
ALWAYS BONDS TO T=Thymine
 G=Guanine ALWAYS BONDS TO C=Cytosine
•What does DNA do?
 DNA
contains all of the instructions
necessary to build and operate a living
organism.
 DNA
molecules can be found inside the cells of
all living things.
•What does this mean?
 DNA
is found inside the cells of all living
things, and that the structure of the DNA
molecule is the same in all living things.
•What does this mean?
 Because
the structure of the DNA
molecule is the same in all living things…
the diversity of life is the
result of differences
within the DNA
sequence.
•How does DNA replicate?
 In
DNA replication, the double-helix “ladder”
is untwisted and the two strands are
separated by breaking the hydrogen bonds
between the base pairs.
 Next, two new strands are made by reading
each side of the DNA ladder, one step (base)
at a time.
 At
each step, the matching base fills in (with its
associated sugar and phosphate) to complete the
rung and lengthen the new DNA strand. When the
 When
the process is complete, there are two
identical DNA double-helices, each
containing one original and one new strand.
RNA
Edited by: Mr. Cistaro
01/13/13
•What is RNA?
 Ribonucleic
 Made
Acid
up of 4 “chemical bases”
 A=Adenine
 G=Guanine
 T=Thymine
 U=Uracil
 C=Cytosine
 Made
up of 1 “backbone”
 Sugar
(Ribose)
 Phosphate
 The
base bonds to the sugar
•What is RNA?
 When
it comes to RNA…
 A=Adenine
ALWAYS BONDS TO U=Uracil
 G=Guanine ALWAYS BONDS TO C=Cytosine
•What does RNA do?
 RNA
reads the DNA, copies a gene
(transcription) and moves to the ribosomes
where it is “read” (translation).
 Each
3 base pairs code for an amino acid.
 Recall that a protein is made up of many
amino acids.
•What does this mean?
•What does this mean?
 Remember
how the structure of the DNA
molecule is the same in all living things?
 Turns out that the Genetic Code is the
same too!
•To recap
•
•
•
•
After a cell has “chosen” a gene from which it will build a
protein, it makes a copy of the information in the form of
messenger ribonucleic acid (mRNA) to send to the
protein-building machinery.
The synthesis of a RNA molecule from a DNA template is
referred to as transcription.
The structure of RNA is very similar to DNA in that it has a
sugar-phosphate backbone to which the chemical bases
are attached.
However, there are some important differences:
•
•
•
•
(1) RNA is single-stranded and therefore does not form a
double helix
(2) the sugar used to form the backbone is slightly different
(3) the chemical base thymine (T) is replaced by uracil (U)
The synthesis of amino acids from a RNA template is
referred to as translation
•LAST SLIDE!
 Questions?